Plasma processing method and plasma processing apparatus

ABSTRACT

A plasma processing method includes providing a substrate having a recess is provided in a processing container; generating plasma in the processing container to form a film on the recess; monitoring a state of the plasma generated in the generating; and determining necessity of re-execution of the generating and processing conditions for the re-execution based on the monitored plasma state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese PatentApplication No. 2020-092244 filed on May 27, 2020 with the Japan PatentOffice, the disclosure of which is incorporated herein in its entiretyby reference.

TECHNICAL FIELD

The present disclosure relates to a plasma processing method and aplasma processing apparatus.

BACKGROUND

As the integration of a semiconductor device progresses in a verticaldirection as well as in a horizontal direction, the aspect ratio of apattern formed in the manufacturing process of the semiconductor deviceis also increasing. For example, in the manufacturing of a 3D NAND, achannel hole is formed in a direction in which the channel hole passesthrough many metal wiring layers. When memory cells of 64 layers areformed, the aspect ratio of the channel hole is as high as 45.

Various methods have been suggested in order to form a pattern having ahigh aspect ratio with high accuracy. For example, a method has beensuggested in which etching and film formation are repeatedly executedfor an opening formed in a dielectric material of a substrate so thatlateral etching is suppressed (U.S. Patent Laid-open Publication No.2016/0343580). In addition, a method has been suggested in which etchingand film formation are combined, so that a protective film forpreventing lateral etching of a dielectric layer is formed (U.S. PatentLaid-open Publication No. 2018/0174858).

SUMMARY

According to one aspect of the present disclosure, a plasma processingmethod realized by a plasma processing apparatus includes a process (a),a process (b), and a process (c). In the process (a), a substrate havinga recess is provided in a processing container. In the process (b),plasma is generated in the processing container to form a film on therecess. In the process (c), a state of the plasma generated in theprocess (b) is monitored. Necessity of re-execution of the process (b)and a processing condition for the re-execution are determined based onthe monitored plasma state.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating an example of the configuration of aplasma processing system according to an embodiment.

FIG. 2 is a view illustrating an example of the configuration of aplasma processing apparatus according to the embodiment.

FIG. 3 is a flow chart illustrating the schematic flow of plasmaprocessing according to the embodiment.

FIGS. 4A to 4D are views for explaining an example of the flow ofsub-conformal atomic layer deposition (ALD).

FIGS. 5A to 5C are views for explaining another example of the flow ofsub-conformal ALD.

FIG. 6 is a flow chart for further explaining the plasma processingaccording to the embodiment.

FIG. 7 is a flow chart for explaining a monitoring process and adetermination process according to the embodiment.

FIG. 8 is a view for explaining the monitoring result obtained in themonitoring process according to the embodiment.

FIG. 9A is a view for explaining Method Example 2 of detecting aphysical quantity in the monitoring process according to the embodiment.

FIG. 9B is a view illustrating an example in which an image obtained byMethod Example 2 of FIG. 9A is digitized.

FIG. 10 is a flow chart illustrating an example of the flow of themonitoring process based on Method Example 2 in FIGS. 9A and 9B.

FIGS. 11A and 11B are views illustrating an example of informationstored in a storage in the plasma processing according to theembodiment.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The illustrativeembodiments described in the detailed description, drawings, and claimsare not meant to be limiting. Other embodiments may be utilized, andother changes may be made without departing from the spirit or scope ofthe subject matter presented here.

Hereinafter, the disclosed embodiments will be described in detail withreference to drawings. The embodiments are not limited. In addition, theembodiments may be properly combined in a range where processingcontents do not contract with each other. In the drawings, the same orcorresponding parts will be denoted by the same reference numerals.

In the following description, the “pattern” refers to the entire shapeformed on a substrate. The pattern refers to all of the plurality ofshapes formed on the substrate, such as, for example, a hole, a trench,and a line and space. In addition, the “recess” refers to a portion of ashape recessed in a thickness direction of the substrate, in the patternformed on the substrate. In addition, he recess has a “side wall” as aninner peripheral surface of the recessed shape, a “bottom” as a bottomportion of the recessed shape, and a “top” that is a substrate surfacecontinuous to the side wall, near the side wall. In addition, a spacesurrounded by the top is called an “opening.” The term “opening” is alsoused to refer to the entire space surrounded by the bottom and the sidewall of the recess, or any position of the space.

It is known that a shape abnormality is likely to occur when a deep holehaving a high aspect ratio, such as a high aspect ratio contact (HARC),is formed. For example, a shape abnormality called bowing is known. Thebowing is a shape abnormality in which when an opening is formed in avertical direction, the inner peripheral surface of the opening bulgesin a barrel shape in a lateral direction. In the embodiment, a film isformed on the side wall of the opening in order to suppress theoccurrence of the shape abnormality such as bowing. Examples of the filmformation method include atomic layer deposition (ALD), plasma-enhancedALD (PEALD), chemical vapor deposition (CVD), plasma-enhanced CVD(PECVD), and plasma enhanced cyclic chemical vapor deposition (PECCVD).

(Configuration Example of Plasma Processing System According toEmbodiment)

FIG. 1 is a view illustrating an example of a plasma processing systemthat may be used to carry out plasma processing according to theembodiment.

A plasma processing system 1000 illustrated in FIG. 1 includes acontroller Cnt, a stage 1122 a, a stage 1122 b, a stage 1122 c, a stage1122 d, a storage container 1124 a, a storage container 1124 b, astorage container 1124 c, a storage container 1124 d, a loader moduleLM, a load lock chamber LL1, a load lock chamber LL2, a transfer chamber1121, and a plasma processing apparatus 1010. The plasma processingapparatus 1010 may be, for example, a plasma processing apparatus 1illustrated in FIG. 2 .

The controller Cnt is a computer including, for example, a processor, astorage, an input device, and a display device, and controls each ofunits (to be described later) in the plasma processing system 1000. Thecontroller Cnt is connected to, for example, a transfer robot Rb1, atransfer robot Rb2, an observation device OC, and the plasma processingapparatus 1010. The controller Cnt may also double as a controller 100of the plasma processing apparatus 1 illustrated in FIG. 2 .

The controller Cnt sends out control signals by operating according to acomputer program (a program based on an input recipe) for controllingeach of units of the plasma processing system 1000. By the controlsignals from the controller Cnt, each of units of the plasma processingsystem 1000, for example, the transfer robots Rb1 and Rb2, and theobservation device OC, and each of units of the plasma processingapparatus 1010 are controlled. In the plasma processing apparatus 1010,according to the control signals from the controller Cnt, it is possibleto control the selection and the flow rate of a gas to be supplied froma gas supply source 15, the exhaust of an exhaust device 65, the powersupply from radio-frequency power supplies 32 and 34, and the coolantflow rate and the coolant temperature. Each process of a substrateprocessing method according to the first and second embodiments may beexecuted when each of units of the plasma processing system 1000 isoperated under the control by the controller Cnt. In the storage of thecontroller Cnt, a computer program for executing a plasma processingmethod according to the embodiment, and various data used for executionare stored in a readable manner.

The stages 1122 a to 1122 d are arranged along one edge of the loadermodule LM. The storage containers 1124 a to 1124 d are provided on thestages 1122 a to 1122 d, respectively. Wafers W may be accommodated inthe storage containers 1124 a to 1124 d.

The transfer robot Rb1 is provided in the loader module LM. The transferrobot Rb1 takes out a wafer W accommodated in any one of the storagecontainers 1124 a to 1124 d, and transports the wafer W to the load lockchamber LL1 or LL2.

The load lock chambers LL1 and LL2 are provided along another edge ofthe loader module LM, and are connected to the loader module LM. Theload lock chambers LL1 and LL2 constitute a preliminary decompressionchamber. The load lock chambers LL1 and LL2 are individually connectedto the transfer chamber 1121.

The transfer chamber 1121 is a chamber capable of being depressurized,and the transfer robot Rb2 is provided in the transfer chamber 1121. Theplasma processing apparatus 1010 is connected to the transfer chamber1121. The transfer robot Rb2 takes out the wafer W from the load lockchamber LL1 or the load lock chamber LL2, and transports the wafer W tothe plasma processing apparatus 1010.

The plasma processing system 1000 includes the observation device OC.The observation device OC may be provided at any location in the plasmaprocessing system 1000. As an example, the observation device OC isprovided in an observation module OM adjacent to the loader module LM.The wafer W may be moved by the transfer robot Rb1 and the transferrobot Rb2, between the observation module OM and the plasma processingapparatus 1010. After the wafer W is accommodated in the observationmodule OM by the transfer robot Rb1, and the alignment of the wafer W isperformed in the observation module OM, the observation device OCmeasures a groove width of, for example, a mask pattern on the wafer W,and transmits the measurement result to the controller Cnt. In theobservation device OC, the groove width of, for example, a mask patternformed on a plurality of regions of the top surface of the wafer W maybe measured. The result of measurement by the observation device OC isused as, for example, a “detection result” in the embodiment to bedescribed later (see FIGS. 11A and 11B). As for the observation deviceOC, for example, an optical observation device, a weight scale, and anultrasonic microscope may be used.

(Configuration Example of Plasma Processing Apparatus According toEmbodiment)

The plasma processing apparatus 1 according to the embodiment of thepresent disclosure will be described with reference to FIG. 2 . FIG. 2illustrates a vertical cross section of an example of the configurationof the plasma processing apparatus 1 according to the embodiment. Theplasma processing apparatus 1 according to the embodiment is a parallelplate type plasma processing apparatus (a capacitively coupled plasmaprocessing apparatus) in which a stage 20 and a gas shower head 25 aredisposed while facing each other in a processing container 10. The stage20 has a function of holding a semiconductor substrate (hereinafter,simply referred to as a “wafer W”) and functions as a lower electrode.The gas shower head 25 has a function of supplying a gas into theprocessing container 10, in a shower form, and functions as an upperelectrode.

The processing container 10 is cylindrical and is made of, for example,aluminum whose surface has been subjected to an alumite treatment (ananodizing treatment). The processing container 10 is electricallygrounded. The stage 20 is provided on the bottom of the processingcontainer 10, and on the stage 20, the wafer W is placed. The wafer W isan example of a substrate as a plasma processing target.

The stage 20 is made of, for example, aluminum (Al), titanium (Ti), orsilicon carbide (SiC). On the top surface of the stage 20, anelectrostatic chuck 106 is provided to electrostatically attract thesubstrate. The electrostatic chuck 106 has a structure in which a chuckelectrode 106 a is interposed between insulators 106 b.

A DC voltage source 112 is connected to the chuck electrode 106 a, and aDC current is supplied from the DC voltage source 112 to the chuckelectrode 106 a. Accordingly, the wafer W is attracted to theelectrostatic chuck 106 by a Coulomb force.

On the electrostatic chuck 106, an annular focus ring 103 is placedwhile surrounding the periphery of the wafer W. The focus ring 103includes a conductive member, for example, silicon, and causes plasma toconverge toward the top surface of the wafer W in the processingcontainer 10 so as to improve the efficiency of etching.

The stage 20 is supported by a support 104. A coolant flow path 104 a isformed inside the support 104. A coolant inlet pipe 104 b and a coolantoutlet pipe 104 c are connected to the coolant flow path 104 a. Acooling medium, such as, for example, cooling water or brine, outputfrom a chiller 107 circulates through the coolant inlet pipe 104 b, thecoolant flow path 104 a and the coolant outlet pipe 104 c. Accordingly,the stage 20 and the electrostatic chuck 106 are cooled.

A heat transfer gas supply source 85 supplies a heat transfer gas suchas helium gas (He) or argon gas (Ar) to the back surface of the wafer Won the electrostatic chuck 106 through a gas supply line 130. Throughsuch a configuration, the temperature of the electrostatic chuck 106 iscontrolled by the cooling medium circulating through the coolant flowpath 104 a, and the heat transfer gas supplied to the back surface ofthe wafer W. As a result, the substrate may be controlled to apredetermined temperature.

The first radio-frequency power supply 34 is electrically connected tothe gas shower head 25 via a matcher 35. The first radio-frequency powersupply 34 applies radio-frequency power (HF) for plasma excitation of,for example, 60 MHz, to the gas shower head 25. In the embodiment, theradio-frequency power (HF) is applied to the gas shower head 25, but maybe applied to the stage 20. The second radio-frequency power supply 32is electrically connected to the stage 20 via a matcher 33. The secondradio-frequency power supply 32 applies radio-frequency power (LF) forbias of, for example, 13.56 MHz, to the stage 20.

The matcher 35 matches a load impedance to an internal (or output)impedance of the first radio-frequency power supply 34. The matcher 33matches a load impedance to an internal (or output) impedance of thesecond radio-frequency power supply 32. The matcher 35 and the matcher33 function such that when plasma is generated in the processingcontainer 10, the load impedances and the internal impedances of thefirst radio-frequency power supply 34 and the second radio-frequencypower supply 32 are seemingly matched.

The gas shower head 25 includes a ceiling electrode plate 41 having manygas supply holes 55 and a cooling plate 42 on which the ceilingelectrode plate 41 is detachably hung and supported. The gas shower head25 is attached while closing the opening of a ceiling of the processingcontainer 10 via a shield ring 40 that covers the periphery of the gasshower head 25. A gas introduction port 45 that introduces a gas isformed in the gas shower head 25. A center-side diffusion chamber 50 aand an edge-side diffusion chamber 50 b diverging from the gasintroduction port 45 are provided in the gas shower head 25. A gasoutput from the gas supply source 15 is supplied to the diffusionchambers 50 a and 50 b through the gas introduction port 45, is diffusedin each of the diffusion chambers 50 a and 50 b, and is introduced fromthe many gas supply holes 55 toward the stage 20.

An exhaust port 60 is formed on the bottom surface of the processingcontainer 10, and the inside of the processing container 10 is exhaustedby the exhaust device 65 connected to the exhaust port 60. Accordingly,the inside of the processing container 10 may be maintained at apredetermined degree of vacuum. A gate valve G is provided on the sidewall of the processing container 10. By opening/closing of the gatevalve G, the wafer W is loaded and unloaded into/from the processingcontainer 10.

An optical sensor 108 capable of measuring the intensity of light ofeach wavelength in plasma in the processing container 10, through aquartz window 109, is attached to the plasma processing apparatus 1. Theoptical sensor 108 includes a first sensor 108 a and a second sensor 108b. The first sensor 108 a detects the state of plasma generated in theprocessing container 10. The detection result of the first sensor 108 ais used in a monitoring process and a determination process (to bedescribed later). In addition, the second sensor 108 b detects a patternshape on the top surface of the wafer W placed on the stage 20. Thedetection result of the second sensor 108 b is used in first to thirddetection processes (to be described later).

The plasma processing apparatus 1 is provided with the controller 100that controls operations of the entire apparatus. The controller 100includes a central processing unit (CPU) 105, a read only memory (ROM)110 and a random access memory (RAM) 115. The CPU 105 executes desiredprocesses such as a film formation process, a monitoring process, adetermination process, an etching process and first to third detectionprocesses (to be described later) according to various recipes stored inthese storage areas. In the recipes, for example, a process time, apressure (exhaust of a gas), a radio-frequency power or a voltage,various gas flow rates, temperatures in the processing container 10 (forexample, an upper electrode temperature, a side wall temperature of theprocessing container, and an electrostatic chuck temperature), and atemperature of the chiller 107 are described as apparatus controlinformation related to process conditions. These recipes illustratingprocessing conditions or programs may be stored in a hard disk or asemiconductor memory. In addition, the recipes may be set at apredetermined position of a storage area while accommodated in aportable computer-readable storage medium such as a CD-ROM or a DVD.

The controller 100 executes a monitoring process (to be described later)of causing the first sensor 108 a to monitor the plasma state in theprocessing container 10. In addition, the controller 100 executes adetermination process (to be described later) of determining whether there-execution of a film formation process is required based on thedetection result of the first sensor 108 a and determining a processingcondition at the time of re-execution. In addition, the controller 100performs first to third detection processes (to be described later) bydetecting the pattern shape of the wafer W based on the detection resultof the second sensor 108 b.

At the time of plasma processing, the opening/closing of the gate valveG is controlled, and the wafer W is loaded into the processing container10 and is placed on the stage 20. A DC current is supplied from the DCvoltage source 112 to the chuck electrode 106 a, so that the wafer W isattracted to and held by the electrostatic chuck 106 due to a Coulombforce.

Subsequently, a gas for plasma processing, radio-frequency power (HF)for plasma excitation, and radio-frequency power (LF) for bias aresupplied into the processing container 10 to generate plasma. Plasmaprocessing (for example, film formation and etching) is performed on thewafer W by the generated plasma.

After the plasma processing, a DC voltage (HV) having a positivity or anegativity opposite to that at the time of attraction of the wafer W isapplied from the DC voltage source 112 to the chuck electrode 106 a soas to remove electric charges of the wafer W, and separate the wafer Wfrom the electrostatic chuck 106. The opening/closing of the gate valveG is controlled so that the wafer W is unloaded from the processingcontainer 10.

(ALD and Sub-Conformal ALD)

In the embodiment, as for a film formation process, a process usingplasma is executed. The film formation process is not particularlylimited as long as it is a process using plasma. For example, asdescribed above, the PEALD, the PECVD, and the PECCVD may be used.

First, ALD and sub-conformal ALD will be described with reference toFIG. 3 to FIGS. 5A to 5C. FIG. 3 is a flow chart illustrating theschematic flow of plasma processing according to the embodiment. Theprocessing flow illustrated in FIG. 3 is common to the case of ALD andthe case of sub-conformal ALD. FIGS. 4A to 4D are views for explainingan example of the flow of the sub-conformal ALD. FIGS. 5A to 5C areviews for explaining another example of the flow of the sub-conformalALD.

First, a wafer W on which a pattern is formed is provided in theprocessing container 10 (step S11). The wafer W is automatically loadedfrom the gate valve G by the transfer robot Rb2. Then, a first gas (alsocalled a precursor) is introduced from the gas supply source 15 to theprocessing container 10 where the wafer W is disposed (step S12). Afirst component contained in the first gas is adsorbed on the topsurface of the wafer W. Then, the inside of the processing container 10is exhausted (purged) by the exhaust device 65 (step S13). Next, asecond gas (also called a reaction gas) containing a second componentthat reacts with the first component is introduced from the gas supplysource 15 to the processing container 10 to generate plasma of thesecond gas (step S14). The second component forms a film by reactingwith the first component on the wafer W. Then, the inside of theprocessing container 10 is exhausted again by the exhaust device 65(step S15). The controller 100 causes each of units to further execute aprocess such as etching after the film formation in steps S12 to S15(step S16). Then, the controller 100 ends the process in each of unitsof the plasma processing apparatus 1.

Herein, descriptions have been made to the effect that each process isexecuted in one plasma processing apparatus 1. Meanwhile, when theplasma processing system 1000 includes a plurality of plasma processingapparatuses 1010, the film formation process and the etching process maybe executed in different plasma processing apparatuses 1010.

In the ALD, a predetermined component is adsorbed and is reacted on/witha substance pre-existing on the substrate surface in a self-controlmanner so as to form a film. Thus, in the ALD, a sufficient processingtime is generally provided, and thus conformal film formation isrealized. In the case of FIG. 3 , a sufficient long processing time isset for step S12 and step S14. That is, processing conditions in stepS12 and step S14 are set as saturation conditions. Accordingly, theadsorption of the first gas component on the wafer W, and the reactionbetween the first gas component and the second gas component reachsaturation on the top surface of the wafer W so that a conformal film isformed. The conformal film is a film having a uniform thicknessregardless of the position on the wafer W (for example, the position inthe vertical direction).

Whereas, in the sub-conformal ALD, the same process procedure as that inthe ALD is used, while a control is performed such that at least one ofadsorption and reaction of the film formation components does not reachsaturation. That is, in the sub-conformal ALD, the same processprocedure as that in the ALD is used, while the self-controllingadsorption or reaction on the top surface of the wafer W is notcompleted so that a sub-conformal film is formed. The sub-conformal filmis a film whose film thickness varies according to the position on thewafer W (for example, the position in the vertical direction).

At least the following two modes are present as processing modes of thesub-conformal ALD.

(1) A precursor is adsorbed on the entire surface of the wafer W. Areaction gas introduced thereafter is controlled so as not to spreadthroughout the entire surface of the wafer W.

(2) A precursor is adsorbed on only a part of the surface of the waferW. A reaction gas introduced thereafter forms a film only on a portionof the surface on which the precursor is adsorbed.

By using the method (1) or (2), it is possible to form a film whosethickness is gradually decreased from top to bottom, on the side wall ofthe pattern formed on the wafer W.

A wafer W illustrated in FIGS. 4A to 4D includes an etching target filmEL1, and a mask MA. A recess having an opening OP is formed in the stackof the etching target film EL1 and the mask MA.

First, the wafer W is provided in the processing container 10 (step S11in FIG. 3 ). Then, a precursor P is introduced into the processingcontainer 10 in which the wafer W is disposed (FIG. 4A, and step S12 inFIG. 3 ). A sufficient processing time is provided to adsorb theprecursor P so that the precursor P is adsorbed on the entire surface ofthe wafer W (FIG. 4B). When the adsorption of the precursor P iscompleted, the inside of the processing container 10 is purged. Next, areaction gas R is introduced into the processing container 10 (FIG. 4C,and step S14 in FIG. 3 ). The introduced reaction gas R reacts with theprecursor P on the wafer W and gradually forms a film F from the topside of the mask MA. Here, before the formation of the film F reachesthe bottom side of the etching target film EL1, the reaction gas R ispurged. Through a process performed in this manner, in using the ALDmethod, the film F may not be formed on the entire side wall of therecess, and may be formed only on the upper portions of the mask MA andthe etching target film EL1 (FIG. 4D). In FIG. 4D, the film F is formedon the upper portion and the top of the side wall of the recess, and isnot formed on the lower portion and the bottom of the side wall.

Next, the second method will be described with reference to FIGS. 5A to5C. The wafer W illustrated in FIGS. 5A to 5C has the same shape as thewafer W in FIGS. 4A to 4D.

In the example of FIGS. 5A to 5C, the precursor P is adsorbed only onthe upper portion of the wafer W (FIG. 5A). After the precursor P ispurged, the reaction gas R is introduced to the processing container 10(FIG. 5B). Here, since the reaction gas R forms a film through areaction only at the location where the precursor P is adsorbed, thefilm F is formed only on the upper portion of the pattern of the wafer W(FIG. 5C).

(Processing Conditions for Selective Adsorption and Reaction)

FIGS. 4A to 4D correspond to a case where step S14 in FIG. 3 is executedunder unsaturation conditions. In addition, FIGS. 5A to 5C correspond toa case where step S12 in FIG. 3 is executed under unsaturationconditions.

When the processing time in step S12 and step S14 is sufficiently long,the formed film becomes conformal rather than sub-conformal. Thus, inthe sub-conformal ALD, processing conditions are set such that at leastone of adsorption and reaction of the film formation components does notreach saturation.

Processing parameters to be adjusted to realize the sub-conformal ALDare, for example, the temperature of the stage 20 on which the wafer Wis placed, the pressure in the processing container 10, the flow rateand the introduction time of the precursor to be introduced, the gasflow rate and the introduction time of the reaction gas to beintroduced, and the processing time. In addition, in the case of aprocess using plasma, the film formation position may also be adjustedby adjusting the value of radio-frequency (RF) power to be applied forplasma generation. In the case of the process in FIG. 3 , the second gasis formed into plasma in step S14, but the first gas of step S12 mayalso be formed into plasma.

(Example of Flow of Plasma Processing Method According to Embodiment)

FIG. 6 is a flow chart for further explaining a plasma processing methodaccording to the embodiment. In the plasma processing method accordingto the embodiment, the state of plasma generated during a film formationprocess (steps S12 to S15 in FIG. 3 ) is monitored so as to realizehighly accurate determination on the ending timing of the film formationprocess.

First, a wafer W is provided in the processing container 10 (step S61).A pattern is formed on the wafer W in advance. For example, the samerecess as those in FIGS. 4A to 4D, and FIGS. 5A to 5C is formed. Whenboth the etching and the film formation may be executed in the plasmaprocessing apparatus 1, the formation of the recess may also be executedin the plasma processing apparatus 1.

Next, the plasma processing apparatus 1 executes a first detectionprocess (step S62). The first detection process is a process in whichthe pattern shape on the wafer W is detected by the second sensor 108 bor the observation device OC, so that the controller 100 determinesprocessing conditions of a subsequent film formation process (step S63)based on the detection result. The pattern shape includes, for example,the aspect ratio of a recess or a surface profile. The first detectionprocess may be performed at any time before or after the process ofproviding the wafer W (step S61) as long as the time is prior to thefilm formation process (step S63). The processing conditions of the filmformation process (step S63) include, for example, the introductionamount of a first gas, the introduction amount of a second gas, areaction time between the first gas and the second gas, a purging time,and the number of cycles. The first detection process will be describedlater.

The controller 100 sends an instruction to each of units of the plasmaprocessing apparatus 1 based on the processing conditions determined bythe first detection process, to start the film formation process (stepS63). First, the controller 100 introduces the first gas from the gassupply source 15 into the processing container 10 (step S631). When theprocessing time determined by the processing conditions has elapsed, thecontroller 100 ends the introduction of the first gas. The first gas isadsorbed on the top surface of the wafer W on the stage 20.

Next, the controller 100 controls the exhaust device 65 to purge the gasin the processing container 10 (step S632).

Next, the controller 100 introduces the second gas from the gas supplysource 15 into the processing container 10 (step S633). The controller100 also applies radio-frequency power (HF) for plasma excitation fromthe first radio-frequency power supply 34 to the gas shower head 25. Thecontroller 100 also applies radio-frequency power (LF) from the secondradio-frequency power supply 32 to the stage 20. The radio-frequencypower (HF) may also be applied to the stage 20. Due to application ofthe radio-frequency power (LF, HF), plasma of the second gas isgenerated in the processing container 10. Then, when the processing timebased on the processing conditions determined by the first detectionprocess has elapsed, the controller 100 ends the introduction of thesecond gas and the plasma generation. A component contained in theplasma of the second gas reacts with a component of the first gas on thetop surface of the wafer W so as to form a film on the top surface ofthe wafer W.

In parallel with the introduction of the second gas, the controller 100executes a monitoring process (step S64A). The monitoring process is aprocess in which the first sensor 108 a monitors the plasma state in theprocessing container 10, and the monitoring result is transmitted to thecontroller 100, and is stored. Details of the monitoring process will bedescribed later.

Next, the controller 100 controls the exhaust device 65 to purge the gasin the processing container 10 (step S634). Accordingly, one cycle ofthe film formation process (step S63) is completed.

Next, the controller 100 executes a determination process (step S64B)based on the monitoring result of the monitoring process (step S64A).The determination process is a process in which the controller 100determines a subsequent process and processing conditions based on themonitoring result transmitted from the first sensor 108 a. Thedetermination process may be executed for each cycle of the filmformation process (step S63), or may be executed after the filmformation process (step S63) is performed for a predetermined number ofcycles.

In the determination process, the controller 100 determines whether tore-execute the film formation process. In addition, when it isdetermined that the film formation process is to be re-executed, thecontroller 100 determines whether to repeat the process from theintroduction of the first gas (step S631), or to repeat the process fromthe introduction of the second gas (step S633). In addition, when it isdetermined to re-execute the film formation process, the controller 100selects processing conditions for the film formation process (step S63).

In FIG. 6 , the determination process (step S64B) is executed afterpurging (step S634), but the determination process (step S64B) may beexecuted before purging or in parallel with purging.

The controller 100 continues the process based on the determinationresult in the determination process. When it is determined to performrepetition from step S631 (step S64B, repeat S631), the controller 100repeats the above-described process in steps S631 to S634. Meanwhile,when it is determined to perform repetition from step S633 (step S64B,repeat S633), the controller 100 repeats the above-described process insteps S633 to S634. In addition, when it is determined not to re-executethe film formation process (step S64B, no re-execution), the controller100 proceeds to a second detection process (step S65).

Similarly to the first detection process, the second detection processis a process in which the pattern shape on the wafer W is detected bythe second sensor 108 b or the observation device OC, so that based onthe detection result, the controller 100 determines a subsequent process(the film formation process (step S63) or the etching (step S66)) andprocessing conditions. The processing conditions of the etching (stepS66) include, for example, the introduction amount of an etching gas,radio-frequency power, and a substrate temperature. The second detectionprocess will be described later.

When it is determined to re-execute the film formation process in thesecond detection process (step S65, re-execute), the controller 100returns to step S63 and repeats the process. Meanwhile, when it isdetermined not to re-execute the film formation process in the seconddetection process (step S65, no re-execution), the controller 100executes etching under the determined processing conditions (step S66).Here, as in the case of the introduction of the second gas, thecontroller 100 may simultaneously execute the monitoring process.

When the etching is ended, the controller 100 executes a third detectionprocess (step S67). Similarly to the first and second detectionprocesses, the third detection process is a process in which the patternshape on the wafer W is detected by the second sensor 108 b or theobservation device OC, so that based on the detection result, thecontroller 100 determines a subsequent process and processingconditions. The third detection process will be described later.

When it is determined to re-execute the film formation process in thethird detection process (step S67, re-execute film formation), thecontroller 100 returns to step S63 and repeats the process. In addition,when it is determined to re-execute the etching process in the thirddetection process (step S67, re-execute etching), the controller 100returns to step S66 and repeats the process. Meanwhile, when it isdetermined to re-execute neither the film formation process nor theetching process in the third detection process (step S67, nore-execution), the controller 100 ends the process. Accordingly, theplasma processing of the embodiment is ended.

(Monitoring Process/Determination Process)

Next, the monitoring process in step S64A and the determination processin step S64B will be described. FIG. 7 is a flow chart for explainingthe monitoring process and the determination process according to theembodiment. In the plasma processing according to the embodiment, in themonitoring process, the controller 100 monitors the state of the plasmagenerated during the film formation process. Then, based on the resultof the monitoring process, the controller 100 executes the determinationprocess of determining the ending timing of the film formation process.

As described above, the monitoring process (step S64A) is executed inparallel with the process of introducing the second gas into theprocessing container 10 and forming the second gas into plasma, in thefilm formation process (step S63). Here, it is assumed that themonitoring process is started at a point in time when the processing ofone wafer W is started.

When the processing of the wafer W is started, the controller 100 causesthe first sensor 108 a to start the monitoring process. When the secondgas is introduced into the processing container 10 and step S633 isstarted, the first sensor 108 a detects the plasma state in theprocessing container 10 (step S71). The timing when the first sensor 108a starts to operate is not particularly limited, and the controller 100may control the first sensor 108 a based on the processing recipe of thewafer W such that the processing is started. In the monitoring process,the first sensor 108 a monitors, for example, the amount of radicalsgenerated by the plasma generation of the second gas.

By the way, the coverage of the film formed on the pattern in the filmformation process is determined by the temperature in the processingcontainer 10, the aspect ratio of the pattern as a processing target,and the dose amount of radicals generated in the processing container10. In the film formation process of the embodiment, the temperature inthe processing container 10 is controlled by the predeterminedprocessing condition, and the aspect ratio of the pattern may be derivedfrom a design value in advance. Thus, if it is possible to know the doseamount of radicals during the film formation process, the coverage ofthe film to be formed by the film formation process may be estimated.Here, the coverage indicates the state of the film, including thethickness and the position of the formed film. For example, the coveragemeans a change in the film thickness according to the aspect ratio.

The amount of radicals included in the plasma may be estimated from, forexample, an electron density, and an ion density of the plasma.Therefore, although the amount of radicals is not directly monitored,another physical quantity indicating the plasma state only has to bemonitored. The physical quantities indicating the plasma state mayinclude, for example, an electron density, an ion density, amolecular⋅radical density, and an atomic⋅molecular ion mass.

These physical quantities indicating the plasma state may be measuredby, for example, spectroscopy (including those using laser), or aninterference⋅reflection method. As for the spectroscopy, emissionspectroscopy for measuring, for example, a radiant flux, an emissionspectrum intensity, or a continuous spectrum intensity may be used. Inaddition, absorption spectroscopy such as a total absorption method, aself-absorption method, or a hook method may be used. In addition,spectroscopy using laser may be used. For example, a laser organicfluorescence method, a laser absorption spectroscopy, and a laserscattering method may be used. In addition, a microwaveinterferometry/reflection method, a laser interferometry/polarizationmethod, or a Schlieren/shadow graph method may be used.

The first sensor 108 a is a detection device capable of monitoring thephysical quantity indicating the plasma state. As long as the physicalquantity indicating the plasma state can be monitored, a specificconfiguration of the first sensor 108 a is not particularly limited. Forexample, as for the first sensor 108 a, an emission spectroscopic(Optical Emission Spectroscopy: OES) sensor may be used. In addition, asfor the first sensor 108 a, an ultra-high resolution image sensor may beused. Then, information acquired by the first sensor 108 a, for example,an image, may be analyzed by the controller 100 so that the physicalquantity may be calculated.

The first sensor 108 a monitors the physical quantity indicating thestate of plasma generated during the process in step S633, and transmitsthe monitoring result to the controller 100. The controller 100 storesthe received monitoring result in association with the timing.

The controller 100 determines whether the film formation process (stepsS631 to S634) has ended (step S72). When it is determined that the filmformation process has not ended (step S72, No), the controller 100returns to step S71, and continues the monitoring process by the firstsensor 108 a. Meanwhile, when it is determined that the film formationprocess has ended (step S72, Yes), the controller 100 proceeds to stepS73 and executes the determination process.

(Determination Process)

In the determination process, the controller 100 calculates theintegrated value on the physical quantity at each timing which isobtained by the monitoring process. The physical quantity obtained bythe monitoring process is stored in the controller 100 in associationwith the timing. FIG. 8 is a view for explaining the monitoring resultobtained in the monitoring process according to the embodiment. In theexample of FIG. 8 , it is assumed that the first sensor 108 a monitorsthe amount of radicals in the plasma at every predetermined time (t₁,t₂, t₃ . . . ) and sends the amount as a numerical value to thecontroller 100. Here, the monitored amount of radicals changes while thecurve in FIG. 8 is drawn. The controller 100 calculates the integratedvalue of the monitoring results from the processing start of the wafer Wto that point in time. In the example of FIG. 8 , the controller 100calculates the total value of S₁, S₂, S₃ . . . .

Next, the controller 100 determines whether the calculated integratedvalue is equal to or greater than a predetermined value (step S73).Here, the “predetermined value” is calculated in advance as an amount ofradicals required until a desired coverage is reached, based on theaspect ratio of the pattern on the wafer W, the temperature in theprocessing container 10, and the desired coverage.

When it is determined that the calculated integrated value is equal toor greater than the predetermined value (step S73, Yes), the controller100 ends the film formation process (step S74). That is, in step S64B ofFIG. 6 , the controller 100 proceeds to the branch of “no re-execution,”and then executes step S65.

Meanwhile, when it is determined that the calculated integrated value isless than the predetermined value (step S73, No), the controller 100determines processing conditions for re-execution of the film formationprocess (step S75). The determined processing conditions may includeprocessing times at the time of re-execution of steps S631 and S633. Forexample, from the integrated value calculated in step S73, if theprocessing times of steps S631 and S633 to be subsequently executed areset to have the same lengths as those in the previous time, in the casewhere a desired coverage is exceeded, the controller 100 sets shortprocessing times for steps S631 and S633. In addition, the determinedprocessing conditions may include a determination on whether to startthe re-execution from step S631 or from step S633. Then, the controller100 re-executes the film formation process under the determinedprocessing conditions (step S76). Then, the controller 100 proceeds tostep S631 or step S633 according to the determined processingconditions.

Since the controller 100 determines the degree of progress of the filmformation process of the wafer W by the integrated value, for example,in the case where the plasma processing apparatus 1 is forcibly endedduring the processing, it is possible to determine processing conditionssubsequent to the recovery of the plasma processing apparatus 1.

(Monitoring Method Example 1 of First Sensor 108 a)

By the way, the first sensor 108 a may monitor the plasma state on abasis of a point, a plane, or a three-dimension. Next, examples of amonitoring method in the monitoring process will be described.

In Method Example 1 of detecting a physical quantity in the monitoringprocess according to the embodiment, when the first sensor 108 a isdisposed on the side surface of the processing container 10 asillustrated in FIG. 2 , an image obtained by monitoring the plasma stateon a basis of a plane in the direction of the side surface of theprocessing container 10 is used. The first sensor 108 a is, for example,an ultra-high resolution image sensor.

In Method Example 1, plasma is displayed as a whitish object which isgradually diffused in the processing space with the lapse of time, inthe obtained image. The diffusion or the intensity of the plasmacorresponds to saturation or brightness of the white portion in theimage. Thus, the controller 100 may acquire the value indicating theplasma state by analyzing the brightness or the saturation of the whiteportion in the obtained image.

The first sensor 108 a transmits the acquired image to the controller100. The controller 100 analyzes the received image, and performscalculation of converting the plasma state into a numerical value basedon, for example, the saturation or the brightness of the image. Then,the integrated value of the calculated numerical values is compared to apredetermined threshold value (the “predetermined value” in FIG. 7 ).Through a process performed in this manner, the controller 100 mayestimate the film formation state on the wafer W, and determine theending timing of the film formation process based on the plasma state inthe vicinity of the wafer W placed in the processing container 10.

(Monitoring Method Example 2 of First Sensor 108 a)

In addition, unlike that illustrated in FIG. 2 , the first sensor 108 amay be disposed not to monitor the processing space in the vicinity ofthe wafer W in the lateral direction of the processing container 10 butto perform monitoring from above the processing container 10 downwards.FIG. 9A is a view for explaining Method Example 2 of detecting aphysical quantity in the monitoring process according to the embodiment.

As illustrated in FIG. 9A, in Method Example 2, the first sensor 108 amonitors the entire surface of the wafer W from above. In the imageillustrated in FIG. 9A, a portion R1 having a relatively large amount ofradicals is displayed as a dark pattern, and a portion R2 having arelatively small amount of radicals is displayed as a light pattern. Thefirst sensor 108 a acquires such an image at every predetermined time(for example, every 50 nanoseconds). Then, the first sensor 108 atransmits the acquired image to the controller 100.

The controller 100 analyzes the image received from the first sensor 108a, and digitizes the shade of a color corresponding to the amount ofradicals. FIG. 9B is a view illustrating an example in which the imageobtained by Method Example 2 of FIG. 9A is digitized. In the exampleillustrated in FIG. 9B, 1, 2, and 3 as digitized values of color shadesare displayed at positions corresponding to the regions (R1 and R2) inFIG. 9A. First, the controller 100 divides a region including the planeof the wafer W into a plurality of regions having uniform areas. Then,an image corresponding to each region is analyzed and is digitized.Accordingly, the controller 100 may obtain the integrated value ofvalues indicating the plasma state in each region for each image.

As illustrated in FIG. 9A and FIG. 9B, when the plane of the wafer W isdivided into a plurality of regions and a numerical value indicating theplasma state of each region is obtained, the controller 100 maydetermine the film formation state at each in-plane position of thewafer W. Thus, the controller 100 may also use the result of themonitoring process in improving the in-plane uniformity of the plasmaprocessing. For example, according to the result of the monitoringprocess, the controller 100 may adjust the radio-frequency power to beapplied to the stage 20 and the gas shower head, among processingconditions for a subsequent process, to different values depending onthe in-plane position.

FIG. 10 is a flow chart illustrating an example of the flow of themonitoring process based on Method Example 2 in FIG. 9A and FIG. 9B. Inthe example of FIG. 10 , first, when the monitoring process is started,the first sensor 108 a starts to monitor the plasma state, and theacquired information is transmitted to the controller 100 and is stored(step S1101). Here, the first sensor 108 a monitors the entire surfaceof the wafer W.

The controller 100 analyzes the received information, for example, animage, and calculates a numerical value indicating the plasma state foreach of preliminary set regions (step S1102). Then, for each of theregions, the controller 100 calculates an integrated value in the filmformation process executed until now, based on the calculated numericalvalues (step S1103). The controller 100 calculates a difference in thecalculated integrated value between the regions (step S1104).

Next, the controller 100 determines whether the integrated valuecalculated in step S1103 is equal to or greater than a predeterminedvalue (step S1105). Then, when it is determined that the integratedvalue is equal to or greater than the predetermined value (step S1105,Yes), the controller 100 determines whether the difference calculated instep S1104 is equal to or lower than a predetermined value (step S1106).Then, when it is determined that the difference is equal to or lowerthan the predetermined value (step S1106, Yes), the controller 100 endsthe film formation process (step S1107). Then, the controller 100proceeds to step S65.

Meanwhile, when it is determined that the integrated value calculated instep S1103 is less than the predetermined value (step S1105, No), thecontroller 100 determines processing conditions for re-executing thefilm formation process (step S1108). Then, the film formation processbased on the determined processing conditions is executed (step S1109).In this case, the film formation process is re-executed based on theprocessing conditions determined in step S1108 and the processing step(S631 or S633) as a re-execution target.

Meanwhile, when it is determined that the difference calculated in stepS1104 is greater than the predetermined value (step S1106, No), thecontroller 100 determines processing conditions for canceling thedifference in order to improve the in-plane uniformity (step S1110).Then, the controller 100 re-executes the film formation process based onthe determined processing conditions (step S1109). Subsequently, theprocess proceeds to step S631 or S633. Accordingly, the monitoringprocess of Method Example 2 is ended.

As described above, in the plasma processing according to theembodiment, by monitoring the plasma state in the processing container10, it is possible to estimate the film formation state withoutinspecting the pattern itself on the wafer W. Thus, the plasmaprocessing apparatus 1 according to the embodiment may highly accuratelyand simply determine the ending timing of the film formation process.

Next, the first to third detection processes will be described. Here,descriptions will be made on the assumption that the detection in thefirst to third detection processes is executed by the second sensor 108b. Meanwhile, the detection in the first to third detection processesmay be executed by the observation device OC after the wafer W istransported to the observation module OM illustrated in FIG. 1 .

(First Detection Process)

The first detection process includes a process of detecting the shape orthe dimension of the pattern on the wafer W by the second sensor 108 b,and a process of determining processing conditions of a subsequentprocess by the controller 100 based on the detection result of thesecond sensor 108 b.

The second sensor 108 b detects the shape or the dimension of thepattern on the wafer W through an optical method. The detection methodby the second sensor 108 b is not particularly limited. The result ofdetection by the second sensor 108 b is transmitted to the controller100, and is stored in the storage such as the ROM 110, or the RAM 115.

When the detection result is received, the controller 100 compares thedetection result to a predetermined pattern dimension. Then, adifference between the predetermined pattern dimension and the detecteddimension is calculated. The controller 100 adjusts processingconditions of a subsequent process based on the calculated difference.Then, the controller 100 determines processing conditions to be used inthe subsequent process.

At a point in time when the wafer W is disposed in the processingcontainer 10, in the case where the pattern formed on the wafer Wdeviates from a design value, when a subsequent process is executedunder processing conditions based on a design, there is a highpossibility that the state of a film to be finally formed may deviatefrom a design value. Therefore, in the embodiment, in the firstdetection process, the processing conditions are adjusted based on adifference between the design value and the actually measured value.

(Second Detection Process)

The second detection process includes a process of detecting the shapeor the dimension of the pattern on the wafer W by the second sensor 108b, and a process of determining a subsequent process and processingconditions by the controller 100 based on the detection result of thesecond sensor 108 b.

The detection process of the second sensor 108 b in the second detectionprocess is the same as the detection process in the first detectionprocess. Meanwhile, at the time of execution of the second detectionprocess, since the film formation process has ended, the shape of thepattern formed on the wafer W is different from that at the time of thefirst detection process. In addition, in the process of the controller100, a predetermined pattern dimension to be compared to the detectionresult is also different from that at the time of the first detectionprocess.

When the detection result is received, the controller 100 compares thedetection result to the predetermined pattern dimension. Then, adifference between the predetermined pattern dimension and the detecteddimension is calculated. The controller 100 determines whether tore-execute the film formation process (step S63) based on the calculateddifference. For example, when the calculated difference is equal to orgreater than a threshold value, the controller 100 determines tore-execute the film formation process. Meanwhile, when the calculateddifference is less than the threshold value, the controller 100determines not to re-execute the film formation process.

When it is determined not to re-execute the film formation process,next, the controller 100 determines processing conditions of subsequentetching (step S66). For example, when the numerical value of thethickness of the film formed on the pattern, which is obtained from thedetection result, is greater than a set value, the processing conditionsare adjusted such that the etching effect becomes stronger. Then, thecontroller 100 determines the adjusted processing conditions, asprocessing conditions for etching (step S66).

When the second sensor 108 b used in the second detection process is,for example, an infrared sensor, the second sensor 108 b may directlymeasure the thickness of the film formed on the pattern. In this case,the controller 100 calculates a difference by comparing the result ofdetection by the second sensor 108 b to a predetermined film thickness.Then, the controller 100 determines whether to re-execute the filmformation process (step S63) based on the calculated difference. Then,the controller 100 determines a subsequent process and processingconditions.

(Third Detection Process)

The third detection process includes a process of detecting the shape orthe dimension of the pattern on the wafer W by the second sensor 108 b,and a process of determining a subsequent process and processingconditions by the controller 100 based on the detection result of thesecond sensor 108 b.

The detection process of the second sensor 108 b in the third detectionprocess is the same as the detection process in the first and seconddetection processes. Meanwhile, at the time of execution of the thirddetection process, since the film formation process and the etchingprocess have ended, the shape of the pattern formed on the wafer W isdifferent from that at the time of the first and second detectionprocesses. In addition, in the process of the controller 100, apredetermined pattern dimension to be compared to the detection resultis also different from that at the time of the first and seconddetection processes.

When the detection result is received, the controller 100 compares thedetection result to the predetermined pattern dimension. Then, adifference between the predetermined pattern dimension and the detecteddimension is calculated. The controller 100 determines whether tore-execute the film formation process (step S63) based on the calculateddifference. For example, when the calculated difference is equal to orgreater than a threshold value, and the detected dimension is smallerthan the predetermined pattern dimension, the controller 100 determinesto re-execute the film formation process. Meanwhile, when the calculateddifference is less than the threshold value, the controller 100determines not to re-execute the film formation process. In addition,the controller 100 determines whether to re-execute the etching process(step S66) based on the calculated difference. For example, when thecalculated difference is equal to or greater than the threshold value,and the detected dimension is larger than the predetermined patterndimension, the controller 100 determines to re-execute the etchingprocess.

When it is determined to re-execute the film formation process, next,the controller 100 determines processing conditions of the filmformation process. For example, the processing conditions are determinedsuch that a difference between a pattern shape obtained from thedetection result and the predetermined pattern dimension is reduced.Then, the controller 100 executes the film formation process by usingthe determined processing conditions (FIG. 6 , step S67, “re-executefilm formation”).

In addition, when it is determined to re-execute the etching process,next, the controller 100 determines processing conditions of the etchingprocess. For example, the processing conditions are determined such thata difference between a pattern shape obtained from the detection resultand the predetermined pattern dimension is reduced. Then, the controller100 executes the etching process by using the determined processingconditions (FIG. 6 , step S67, “re-execute etching”). When it isdetermined to re-execute neither the film formation process nor theetching process (FIG. 6 , step S67, “no re-execution”), the controller100 ends the process.

All of the first detection process, the second detection process and thethird detection process may be realized by using the same detector, forexample, the second sensor 108 b or the observation device OC, ordifferent detectors may be used for the processes, respectively. Inaddition, the determination process may be executed by the controller100, or the first sensor 108 a may have a determination function so thata numerical value and a time stamp may be transmitted to the controller100.

FIGS. 11A and 11B are views illustrating an example of informationstored in the storage in the plasma processing according to theembodiment. In the example illustrated in FIG. 11A, the results detectedin the first detection process, the second detection process, and thethird detection process are stored in association with “time stamp.”Here, the detection result may be a specific dimension. In addition,shape abnormalities may be categorized in advance and a plurality oftypes may be defined, so that a type corresponding to the detectionresult may be stored. In FIG. 11A, the detection results are categorizedand are stored as, for example, “dimension A,” “dimension B,” etc. Inaddition, as the result of the monitoring process, numerical valuesassociated with a plurality of time stamps may be stored, in associatedwith a time stamp each time step S633 is executed once. In addition,when the first sensor 108 a is an image sensor, a plurality of imagesthemselves may be stored. In FIG. 11A, as the monitoring result, a value“V1” obtained by digitizing each of images acquired during step S633,and integrating the digitized values is stored. In addition, in FIG.11A, as the “determination result”, results of the first to thirddetection processes and the determination process are stored. Forexample, in the first detection process, a processing condition “X” fora subsequent process is stored. For example, in the second detectionprocess, “re-execute” indicating re-execution of the film formationprocess, and a processing condition “Y” for the re-execution are stored.“Y” also includes information that identifies the step in which theprocess is executed. In addition, in the third detection process, “donot re-execute” indicating that neither etching nor film formation isre-executed is stored. In addition, due to no re-execution, “NA” (notapplicable) is stored in the column of the processing condition. Inaddition, “re-execute” and “condition X” are stored in association withthe monitoring process “V1.” This indicates that in the determinationprocess, it has been determined that the film formation process is to bere-executed, and the corresponding processing condition is “X.”

In addition, FIG. 11B is a configuration example when a dimension or athreshold value to be compared to a detection result in each process isstored in the storage. For example, in the first detection process, thedetection result is compared to “dimension AA” so as to determine theprocessing condition of a subsequent process. FIGS. 11A and 11B are anexample, and the configuration of information stored in the storage toexecute the first to third detection processes, the monitoring processand the determination process is not particularly limited.

(Modification)

In the above-described embodiment, the detection result of the firstdetection process (step S62), the monitoring result of the monitoringprocess (step S64A), the detection result of the second detectionprocess (step S65), and the detection result of the third detectionprocess (step S67) are used in, for example, adjusting processingconditions, and determining re-execution necessity of each process, inregard to the wafer W on which the processes have been executed.However, these detection results and the monitoring result may also beapplied to not only the wafer W on which the processes have beenexecuted, but also a wafer W′ to be processed after the wafer W. Thatis, a series of processes (steps S61 to S67) are executed on the waferW, and data is acquired in regard to, for example, the shape of therecess before the film formation process, the plasma state in the filmformation process, the state of the film formed by the film formationprocess, and the state of the film and the shape of the pattern afterthe etching. Then, correlation between these is obtained. As an example,correlation is obtained in regard to the shape of the recess before thefilm formation process, the plasma state in the film formation process,and the state of the film formed by the film formation process. Inanother example, correlation is obtained in regard to the plasma statein the film formation process, the state of the film formed by the filmformation process, and the state of the film and the pattern shape afterthe etching. These correlations may be stored as physical models in thestorage in the controller Cnt. Then, conditions of the film formationprocess (step S63) or the etching (step S66) are corrected based onthese physical models, and the corrected conditions are applied to theprocessing of the wafer W′. In an example, the physical models areconstructed by repeating a cycle including processing execution,correlation acquisition, and condition correction. The construction ofthe physical models may be performed by machine learning. According tosuch a modification, the processing on the wafer W may be performed in ashorter time with higher accuracy than the processing on the wafer W.

(Effect of Embodiment)

The plasma processing method according to the embodiment includes aprocess (a), a process (b), a process (c), and a process (d). In theprocess (a), a substrate having a recess is provided in a processingcontainer. In the process (b), plasma is generated in the processingcontainer to form a film on the recess. In the process (c), a state ofthe plasma generated in the process (b) is monitored. In the process(d), necessity of re-execution of the process (b) and a processingcondition for the re-execution are determined based on the monitoredplasma state. Thus, according to the plasma processing method accordingto the embodiment, there is no need to inspect the pattern itself on thesubstrate, and by estimating the film formation state, it is possible todetermine the necessity of re-execution of the film formation processand the processing condition suitable for a case of the re-execution. Inaddition, in the present plasma processing method, in order to monitorthe plasma state during the film formation process, it is possible toestimate the film formation state without carrying the substrate out ofthe processing container. Thus, according to the present plasmaprocessing method, it is possible to easily determine the ending timingof the film formation process with high accuracy. Thus, in the presentplasma processing method, it is possible to stabilize the performance ofthe film formation process using plasma.

In addition, in the plasma processing method according to theembodiment, the process (b) may include a process (b-1) and a process(b-2). In the process (b-1), a first gas may be introduced into theprocessing container and may be adsorbed on the recess. In the process(b-2), a second gas may be introduced into the processing container sothat plasma of the second gas may be generated and reacted with acomponent of the first gas adsorbed on the recess to form a film. Then,in the process (c), a state of the plasma generated in the process (b-2)may be monitored. As described above, the plasma processing methodaccording to the embodiment may be applicable to a film formationprocess, for example, ALD, which is realized in two stages of theadsorption of the first gas and the reaction of the second gas.

In addition, the plasma processing method according to the embodiment,the process (b) may be ended before reaction between the component ofthe first gas and the component of the second gas is saturated on anentire surface of the recess. As described above, the plasma processingmethod according to the embodiment may be used to determine the endingtiming of the film formation process in the sub-conformal ALD. Thus,according to the plasma processing method according to the embodiment,the ending timing of the film formation process may be highly accuratelyestimated, and then the film formation process may be ended before thefilm formed by the sub-conformal ALD reaches a saturation state.

In addition, the plasma processing method according to the embodiment,in the process (c), a physical quantity indicating the plasma state maybe monitored. Then, in the process (d), when an integrated value of thephysical quantities obtained by monitoring is less than a predeterminedvalue, re-execution of the process (b) is determined. Thus, according tothe plasma processing method according to the embodiment, based on theintegrated value of the physical quantities obtained by monitoringduring the film formation process, it is possible to highly accuratelyestimate the state of the film formed from the processing start to thatpoint in time. Thus, in the embodiment, even if the film formationprocess is interrupted for some reason, it is possible to estimate thefilm formation state at that point in time based on the monitoringresult, and to resume the film formation process in order to make up forthe shortage.

In addition, the plasma processing method according to the embodiment,in the process (c), an amount of radicals in the plasma generated in theprocess (b) may be monitored. The amount of radicals may be calculatedbased on, for example, an electron density and an ion density. Inaddition, when the temperature in the processing container and thepattern shape on the substrate as a processing target are known, it ispossible to estimate the film formation state based on the amount ofradicals. Thus, according to the embodiment, it is possible to easilyestimate the film formation state on the substrate by using the physicalquantity that may be acquired by, for example, an emission spectroscopicsensor.

In addition, the plasma processing method according to the embodiment,in the process (c), the plasma state in each of regions set in a surfacewhere the substrate is disposed may be monitored. In the process (d),when an integrated value of physical quantities indicating the plasmastate in each of the regions is less than a predetermined value,re-execution of the process (b) is determined. Thus, according to theembodiment, it is possible to determine the necessity of re-execution ofthe film formation process by estimating the film formation state ineach region in the substrate plane.

In addition, the plasma processing method according to the embodiment,in the process (c), the plasma state in each of regions set in a surfacewhere the substrate is disposed may be monitored. Then, in the process(d), physical quantities indicating the plasma state in the regions,respectively, may be compared, and re-execution of the process (b) isdetermined when a difference is larger than a predetermined value. Thus,in the embodiment, it is possible to re-execute the film formationprocess such that the film formation state may become uniform in theregions in the substrate plane. Thus, the plasma processing methodaccording to the embodiment may improve the in-plane uniformity in thefilm formation process.

In addition, the plasma processing method according to the embodimentmay further include a process (e), and a process (f). In the process(e), a state of the film on the recess is detected after the process (b)is executed. In the process (f), the process (b) is re-executedaccording to a detection result of the process (e). Thus, according tothe plasma processing method according to the embodiment, through notonly the monitoring of the plasma state, but also detection of the filmstate, it is possible to determine whether to further re-execute thefilm formation process. Thus, in the embodiment, it is possible tostabilize the performance of the film formation process using plasma andto realize highly accurate film formation.

In addition, the plasma processing method according to the embodimentmay further include a process (e), a process (f), and a process (g). Inthe process (e), a state of the film on the recess is detected after theprocess (b) is executed. In the process (f), processing conditionsaccording to a detection result of the process (e) are determined. Inthe process (g), a base layer of a layer having the film formed on therecess is etched by using the layer as a mask, under the processingconditions determined in the process (f). Thus, in the embodiment,according to the film formation result, it is possible to adjustprocessing conditions of subsequent etching, and to realize highlyaccurate pattern formation.

In addition, the plasma processing method according to the embodimentmay further include a process (h). In the process (h), after the process(g) is executed, a shape of a pattern formed by the etching and/or thestate of the film on the recess are detected, and then the process (b)or the process (g) is re-executed when a degree of coincidence betweenthe detected shape and a predetermined shape is equal to or lower than apredetermined value. Thus, in the embodiment, it is possible todetermine whether to further execute etching according to the shapeafter the etching. Thus, in the embodiment, it is possible to realizehighly accurate pattern formation.

In addition, the plasma processing method according to the embodimentmay further include a process (i) and a process (j). In the process (i),a shape of the recess is detected before the process (b) is executed. Inthe process (j), processing conditions of the process (b) are determinedaccording to a detection result of the process (i). Thus, in theembodiment, it is possible to determine processing conditions accordingto the state of the pattern on the substrate before the film formationor the etching is executed. Thus, in the embodiment, it is possible torealize highly accurate pattern formation.

In addition, the plasma processing method according to the embodimentmay further include a process (k), a process (l), and a process (m). Inthe process (k), correlation between the shape of the recess before filmformation, the plasma state, and the state of the film formed in theprocess (b) is obtained based on the shape of the recess of thesubstrate before execution of the process (b), the plasma statemonitored in the process (c), and the state of the recess of thesubstrate after execution of the process (b). In the process (l), theprocessing conditions in the process (b) are corrected based on theobtained correlation. In the process (m), plasma processing is executedby applying the corrected processing conditions to a substrate (asubstrate to be processed after the substrate) different from thesubstrate on which, for example, the process (k), the process (l) andthe process (m) have been executed. Thus, in the embodiment, each timethe film formation process is executed on the substrate, it is possibleto optimize the film formation conditions.

In addition, the plasma processing method according to the embodimentmay include a process (n), a process (o), a process (p), and a process(q). In the process (n), after the process (g) is executed, a shape of apattern formed by the etching and/or the state of the film on the recessare detected. In the process (o), correlation between the state of thefilm before and after the process (g), the plasma state, and the shapeof the pattern after the process (g) is obtained based on the state ofthe film detected in the process (e), the plasma state monitored in theprocess (c), and the shape of the pattern and/or the state of the filmon the recess detected in the process (n). In the process (p), theprocessing conditions in the process (g) are corrected based on theobtained correlation. In the process (q), under the corrected processingconditions, a substrate different from the substrate on which, forexample, the process (n), the process (o) and the process (p) have beenexecuted is etched. Thus, in the embodiment, each time the substrate isetched, etching conditions may be optimized.

In addition, the plasma processing apparatus according to the embodimentincludes one or more processing containers and a controller. Inaddition, at least one of one or more processing containers isconfigured to perform etching. At least one of one or more processingcontainers is configured to perform film formation. One processingcontainer may be configured to perform etching and film formation. Theprocessing container includes a gas supply configured to supply aprocessing gas therein. The controller causes each of units to execute aplasma processing method including a process (a), a process (b), aprocess (c), and a process (d). In the process (a), a substrate having arecess is provided in the processing container. In the process (b),plasma is generated in the processing container to form a film on therecess. In the process (c), a state of the plasma generated in theprocess (b) is monitored. In the process (d), necessity of re-executionof the process (b) and processing conditions for the re-execution aredetermined based on the monitored plasma state. Thus, the plasmaprocessing apparatus according to the embodiment may stabilize theperformance of the film formation process using plasma, and may realizehighly accurate pattern formation.

A target to which the plasma processing method according to theembodiment is applied is not particularly limited as long as it issubstrate processing using plasma. In addition, the plasma processingmethod according to the embodiment may be used in a 3D NAND or DRAMmanufacturing process. In addition, the plasma processing methodaccording to the embodiment may be used in, for example, processing of ahigh AR (aspect ratio) organic film, or processing of a mask for logic.

According to the present disclosure, it is possible to stabilize theperformance of a film formation process using plasma.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various Modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. A plasma processing method comprising: (a)providing a plasma processing system including: a plurality of plasmaprocessing apparatuses, at least one of the plurality of plasmaprocesses apparatuses including: a chamber, the chamber including asubstrate support and a plasma generator facing the substrate support,and wherein a substrate having a recess is positioned on the substratesupport in the chamber a first sensor for monitoring a state of plasmagenerated in the chamber, and a controller; an observation deviceincluding a second sensor provided outside the at least one of theplurality of plasma processing apparatuses, (b) detecting a patternshape on the substrate using the second sensor; (c) generating plasma inthe chamber under a first processing condition determined based on theresults of (b), thereby forming a film on the recess, the film beingformed on an upper side of a side wall of the recess and on a topsurface outside of the recess and adjacent the recess, and not beingformed on a lower side of the side wall and a bottom of the recess; (d)monitoring a state of the plasma generated in (c) using the firstsensor; (e) determining, based on the state of the plasma monitored in(d), a necessity of re-execution of (c), and a second processingcondition for the re-execution of of (c); (f) detecting, using thesecond sensor, a pattern shape of the substrate on which the film isformed when it is determined in (e) that (c) is not to be re-executed;(g) etching a base layer under a third processing condition determinedbased on the results of (f), the etching of the base layer includingusing a layer having the film formed thereon as a mask; wherein (c)includes: (c-1) introducing a first gas into the chamber and causing thefirst gas to be adsorbed on the recess, (c-2) purging an inside of thechamber, (c-3) introducing a second gas into the chamber to generate theplasma from the second gas and reacting a component of the second gaswith a component of the first gas adsorbed on the recess, therebyforming the film, (c-4) purging the inside of the chamber, and (c-5)repeating (c-1), (c-2), (c-3), and (c-4) in a cycle, and wherein: atleast one of: (1) in (c-1), the gas is adsorbed on only a part of therecess, and/or (2) in (c-3), (c-3) is ended before a reaction betweenthe component of the first gas and the component of the second gas issaturated over an entire surface of the recess, in (c), the film isformed on the side wall such that a thickness of the film graduallydecreases from the upper side of the side wall toward a bottom of therecess, (d) includes monitoring the state of the plasma in each of aplurality of regions where the substrate is disposed, in (e), (c) isdetermined to be re-executed when an integral value of a physicalquantity obtained in (d) that is indicative of the state of the plasmain each of the plurality of regions is less than a predetermined value,the physical quantity including at least one parameter selected from aparameter group consisting of an electron density, an ion density, amolecular radical density, and an atomic molecular ion mass, (e) isperformed before (c-4), after (c-4), or in parallel with (c-4), and (g)is performed in a different plasma processing apparatus than (c), andwherein: the first processing condition includes at least one selectedfrom a parameter group consisting of a temperature of a stage on whichthe substrate is disposed, a pressure of the chamber, an introductionflow rate of the first gas, an introduction time of the first gas, and aprocessing time, the second processing condition includes at least oneof a processing time for re-executing (c-1), a processing time forre-executing (c-3), re-executing (c) starting from (c-1), andre-executing (c) starting from (c-3), the third processing conditionincludes at least one of an introduction amount of an etching gas, aradio-frequency power, and a substrate temperature.
 2. The plasmaprocessing method according to claim 1, wherein in (c), a sub-conformalfilm is formed on the recess.
 3. The plasma processing method accordingto claim 1, wherein in (c-3), a position where the film is formed on therecess is controlled by adjusting at least one parameter selected from aparameter group consisting of a temperature of a stage on which thesubstrate is disposed, a pressure of the chamber, an introduction flowrate of the second gas, an introduction time of the second gas, aprocessing time, and a radio-frequency power for plasma generation. 4.The plasma processing method according to claim 1, wherein in (d), anamount of radicals in the plasma generated in (c) is monitored.
 5. Theplasma processing method according to claim 1, wherein in (e), physicalquantities indicating the state of the plasma state in the regions arecompared, and when a difference is larger than a predetermined value,re-execution of (c) is determined.
 6. The plasma processing methodaccording to claim 1, wherein (f) includes: (f-1) detecting a state ofthe film on the recess after (c); and (f-2) re-executing (c) accordingto a detection result of (f-1).
 7. The plasma processing methodaccording to claim 6, further comprising: (i) detecting a shape of therecess before (c); and (j) determining a processing condition of (c)according to a detection result of (i).
 8. The plasma processing methodaccording to claim 7, comprising: (k) obtaining correlation between theshape of the recess before film formation, the state of the plasma, andthe state of the film formed in (c) based on the shape of the recessdetected in (i), the state of the plasma monitored in (d), and thepattern shape of the substrate detected in (f); (l) correcting theprocessing condition in (c) based on the correlation; and (m) forming afilm on a recess of a substrate different from the substrate under theprocessing condition corrected in (l).
 9. The plasma processing methodaccording to claim 1, wherein (f) includes: (f-1) detecting a state ofthe film on the recess after (c); (f-2) determining a processingcondition according to a detection result of (f-1); and wherein (g)includes etching the base layer under the processing conditiondetermined in (f-2).
 10. The plasma processing method according to claim9, further comprising: (h) detecting a shape of a pattern formed by theetching and/or the state of the film on the recess after (g), andre-executing (c) or (g) when a degree of coincidence between the shapedetected in (h) and a predetermined shape is equal to or lower than apredetermined value.
 11. The plasma processing method according to claim9, comprising: (i) detecting a shape of the recess before (c); (n)detecting a shape of a pattern formed by the etching and/or the state ofthe film on the recess after (g); (o) obtaining correlation between thestate of the film before and after (g), the state of the plasma, and theshape of the pattern after (g) based on the state of the film detectedin (f), the state of the plasma monitored in (d), and the shape of thepattern and/or the state of the film on the recess detected in (n); (p)correcting the processing condition in (g) based on the correlation; and(q) etching a substrate different from the substrate under theprocessing condition corrected in (p).
 12. The plasma processing methodaccording to claim 1, wherein the first sensor monitors a physicalquantity indicating a state of the plasma, and the second sensoroptically determines a quantity relating to the pattern shape on thesubstrate.
 13. The plasma processing according to claim 12, wherein thephysical quantity indicating a state of the plasma is a quantity fromwhich an amount of radicals in the plasma may be estimated.
 14. Theplasma processing method according to claim 1, wherein in (e) variationsin in-plane uniformity are determined based on the state of the plasmamonitored in (d), and further wherein based on determined variations inin-plane uniformity the second processing condition for re-execution of(c) is changed.
 15. A plasma processing method comprising: providing aplasma processing apparatus, the plasma processing apparatus including achamber having a substrate provided therein, the substrate having arecess; generating plasma in the chamber thereby forming a film on therecess, the film being formed on an upper side of a side wall of therecess and on a top surface outside of the recess adjacent the recess,and not being formed on a lower side of the side wall and a bottom ofthe recess; monitoring a state of the plasma generated in the generatingusing a first sensor; detecting a pattern shape on the substrate using asecond sensor; determining a necessity of re-execution of the generatingof the plasma; detecting, using the second sensor, a pattern shape ofthe substrate on which the film is formed when the generating of theplasma is not to be re-executed; etching a base layer using a layerhaving the film formed thereon as a mask; wherein the generating of theplasma includes: introducing a first gas into the chamber and causingthe first gas to be adsorbed on only a part of the recess, andintroducing a second gas into the chamber and reacting a component ofthe second gas with a component of the first gas adsorbed on the recess,thereby forming the film, and wherein: the generating of the plasma isstopped before a reaction between the component of the first gas and thecomponent of the second gas is saturated over an entire surface of therecess, and the film is formed on the side wall such that a thickness ofthe film gradually decreases from the upper side of the side wall towarda bottom of the recess.
 16. The plasma processing method according toclaim 15, wherein the first sensor monitors a physical quantity fromwhich an amount of radicals in the plasma may be estimated, and thesecond sensor optically determines a quantity relating to the patternshape.
 17. The plasma processing according to claim 15, whereinvariations in in-plane uniformity are determined based on themonitoring; and when the generating the plasma is re-executed, at leastone plasma condition is changed based on determined variations in thein-plane uniformity.
 18. The plasma processing method according to claim15, wherein based on the detecting using the second sensor, adetermination is made to re-execute the generating the plasma or to notre-execute the generating plasma, and wherein: in response to adetermination to re-execute the generating the plasma, generating theplasma is re-executed with at least one processing condition changedcompared to an immediately proceeding generating of the plasma; and inresponse to a determination to not re-execute the generating the plasma,the etching is performed.